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					Hydro Power Welding Applications

         Carlos Faggiani, CWI
             SMT – Brasil
          Hydro Power Main Hub for New
                   Projects
                          Estimated Hydro Power Development by
                                         Region




Sandvik Materials Technology
                          Hydro Power trends
 Canada, USA, Brasil, China and Russia producing more
  than 50% of HP energy of the world
 Large dams demands long term studies of enviromental
  impact. Few projects are running, mainly in China, South
  East Asia and South America
 Runners that demands small dams have been considering
  for new projects. The impact on the enviroment is much
  lower than large dams, e.g. Rio Madeira Project in Brazil.
 Small hydro power units have been preferred in
  replacement of large dams projetcs




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                Hydro Power Basic Set UP

                               Water
                     Water feeding pipein


                               Water reservoir

                                 Dam
                                                               Distribution Blades
                                   Vortex
                                                             Suction pipe
                                       Pipe

                                                 Energy transportation

                                                 Generator
                                                  Turbine




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                          Hydro Power Set up
                                      Upper Crosshead
Itaipu Hydroelectric Set up               Upper Shaft
   Source: Voith Siemens
                                          Lower shaft
                                                 Stator

                                   Lower Crosshead
                                Stator support ring

                                   Starting motor                Stainless Steel Welding
                                               Head
                                          Turbine shaft
                                       Hydraulic Turbine
                                  Adjustable Blades
                                           Lower ring
                                          Distribution Blades




                               Water feeding pipe

                                                    Spiral Box

                                              Suction pipe


Sandvik Materials Technology
                           Hydraulic Turbines
 Most Common Materials of Construction
       Past: ASTM A27, surfaced with SS CrNi or CrNiMo alloys – 24Cr-13Ni
        or 19Cr-12Ni-3Mo
       Present: ASTM A743 CA6NM (13Cr-4Ni) . Very few projects asks for
        Nitronic 50 and 248SV

      The material properties demand are erosion-corrosion resistance,
        cavitation resistance and mechanical properties (impact strenght).
        Stainless Steels are the top materials, mainly the soft martensitics.


 Welding is used during the turbine constrution for:
         Joint welding of the blades-turbine boss
         Joint welding of tubine boss body
         Joint welding of blades (adjustable and distributor)
         Rebuild casting defects

Sandvik Materials Technology
                    Hydraulic Turbine types

 The hydraulic turbines are selected according to the
  following parameters:
       Quantity of water available
       Flow rate of the river
       Water column
 Most common types are Pelton, Francis, Kaplan and Bulb




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                               Pelton



                                     Big water column + small
                                      amount of water
                                     Turbine position: Vertical
                                     Examples: Yucan – Peru,
                                     Usual welding process for
                                      construcion: GMAW or FCAW




Sandvik Materials Technology
                                 Francis

      Big amount of water+medium
       water column
      Turbine position: horizontal
      Examples: Three Gorges
       (China), Itaipu and Tucuruí
       (Brazil), El Guri (Venezuela)
      Usual welding process for
       construcion: GMAW or FCAW
       and SAW




Sandvik Materials Technology
                               Kaplan


                                     Small water
                                      column+mediun/big amount
                                      of water
                                     Turbine Position: horizontal
                                     Examples: Caruache –
                                      Venezuela
                                     Usual welding process for
                                      construcion: GMAW or FCAW
                                      and SAW




Sandvik Materials Technology
                               Bulb

                                       Low water column +
                                        medium/high flow rate
                                       Turbine position: vertical
                                       Water reservoiur represents
                                        1/10 of the Francis needs
                                       Examples: Rio Madeira
                                        project (Jirau and Santo
                                        Antonio Dams)
                                       Usual welding process for
                                        construcion: GMAW or FCAW
                                        and SAW




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                               Customers
 OEM new projects / fabrication:
         Alstom Power
         Voith Siemens
         GE
         Westinghouse
         Hitachi
         Andritz (VA Tech)
         Impsa
 Maintenance
       Usually are local companies that is specialist of rebuild the cavited
        blades. The companies could be from the State (government) of 3rd.
        part companies. The OEM seldom do any type of maintenance.




Sandvik Materials Technology
            Summary – Materials and
         Consumables and its application


                                                           Fabrication                                    Maintenance
      Type         Materials      Part      Consumable       Welding Process PWHT        Consumable        Turbine is rebuilded at   Heat treatment
                   CA6NM        turbines   13.4 (410NiMo) GMAW/FCAW and SAW yes         FCAW/GMAW                  in situ                 no
                                                                                      309L/316L/CrCoMn
                                                                                    alloys/Duplex. SMAW
   Francis,
                                                                                        could be used.
   Kaplan, Bulb

                  CA15 or 304 turbines box 309L, 309LMo,    FCAW or SAW      no         FCAW 309L                  in situ                no
                                               308L

      Pelton        CA6NM       turbines   13.4 (410NiMo)   GMAW/FCAW       yes       13.4 (410NiMo)           welding shop               yes




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             Maintenance – SS materials
            performance under cavitation




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           Consumables for maintenance
 Sandvik 13.4 – Soft martensitc type, availble at Sandvik do Brasil ,
  ER410NMo type with premium Impact Strenght (nominal values CVN at 0oC
  >70J, PWHT 580oC/6hrs). Good weldability and feeding properties (GMAW).
  Rebuild of Pelton shells is the only application for this grade.
 SS Austenitic 309L and 316L – Most common consumables used for
  maintenance and new parts of carbon steel base. FCAW is the preferred
  process due its excelent weldability and low availability of pulsed MIG
  machines in the welding shops of maintenance service companies. GMAW is
  growing for maintenance due its eviromental friendly characteristics.
 CrMnCo alloys – Cavitec and Cavitalloy are the most famous brands for these
  class of high cost/high performance materials. For maintanance, the results of
  cavitation and erosion-corrosion resistance are the bests. Their high cost
  limited its application for a few power plants.
 Nitronic 60 (ER218) – Cost alternative for CrMnCo alloys. Some companies
  relates difficulties in weldability. Good resistance of Cavitation.
 Duplex 22.8.3.L – 22Cr type duplex have been investigating for replace SS
  autenitics on maintenance. The cavitation and corrosion erosion properties are
  usually between SS austenitics and CrMoCo alloys. Price alternative for
  CrMnCo alloys when the company is considering cost reduction.
    Note: 22.8.3.L is a potential product to be developed together the service companies.


Sandvik Materials Technology

				
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posted:9/30/2011
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